Writeable file already in use

[Evan Hunt]

On Mon, Jan 04, 2016 at 05:13:55PM -0700, Sathyan Arjunan wrote:
> Recently, I updated my bind from 9.9.5 to 9.9.8-P2 from then I seen
> problems with me named configuration. Interestingly, I seen this problem
> only on my slaves NOT on Master DNS.
> 
> I am using multiple zones pointing to a same file. This configuration has
> been in place for nearly 10 years with no issues...

It's actually an error and always has been.  Having named write to the
same file for multiple zones is risky; they can step on each other and
cause load failures later.  The only change is that named will now
prevent you from making this mistake.

> Zone config on Master: ###No issues with Master###
> 
>  zone "domain1.com." {type master; file "db.file-1"; };
>  zone "domain2.com." {type master; file "db.file-1"; };
>  zone "domain3.com." {type master; file "db.file-1"; };

On the master server, named doesn't write to zone files (unless the
zone is dynamically updatable) so this isn't an error.

> zone "domain1.com." {type slave; file "db.file-1"; masters { x.x.x.x; };
> allow-query { any; }; };
> zone "domain2.com." { type slave; file "db.file-1"; masters { x.x.x.x; };
> allow-query { any; }; };
> zone "domain3.com." { type slave; file "db.file-1"; masters{ x.x.x.x; };
> allow-query { any; }; };
> 
> Below is the errors i seen from named on my slave dns
> 
> : named.conf:584: writeable file 'db.file-1': already in use: named.conf:194

On a slave server, named transfers the zone from elsewhere and writes a
copy into a local file.  These all need to be different files.

> Please advise...

Change the filenames on the slave, or just don't have a "file" option
in the slave zone configuration.

-- 
Evan Hunt -- each at isc.org
Internet Systems Consortium, Inc.